As the political battle rages over the Landmarks Preservation Commission’s authority, the powerful but embattled city agency will hold a public hearing today on the proposed designation of 86 Trinity Place — former home to the American Stock Exchange, originally called the New York Curb Exchange.

The LPC has set a likely June 26 vote on whether to landmark the vacant, 15-story tower with an imposing Art Deco limestone and granite facade. Designation would protect the structure from demolition or alteration without the LPC’s blessing.

The building owners plan to convert it into a retail mecca and a 174-room hotel. And they have alterations very much in mind.

Despite perceptions by landlords that the LPC is too designation-mad and needs reining in, and by preservationists that the panel often caves to political and industry pressure, the 86 Trinity case illustrates how both sides often work behind the scenes to minimize confrontation.

It’s especially common at distinguished properties requiring “adaptive reuse” once their original function no longer exists, such as the former Amex, whose obsolete features include a giant trading floor under a 60-foot ceiling.

In a June 8 letter to LPC Chairman Robert Tierney, Allan Fried, managing member of a partnership with Michael Steinhardt, which paid $17 million for the 14-story building last year, wrote that his company was “honored” the panel is considering it for landmark status.

In remarks that could almost have been written by preservationists, Fried said the former Amex headquarters — consisting of two interconnected structures on Greenwich Street and Trinity Place built in 1921 and 1931, respectively — “occupy an important place” in the city’s financial history, and the Trinity side by architects Starrett & Van Vleck (1931) “has an exuberant Art Deco facade.”

Fried wasn’t available for comment yesterday, but his spokeswoman reiterated he “has no objection to the exterior designation.”

Even so, she said he would likely seek a “certificate of appropriateness” for certain changes they’d need to use the lower floors of 86 Trinity Place for retail. A sign on the Greenwich Street side says retail spaces of 10,000-130,000 square feet are available through Fried’s GHC Development.

Fried hopes to enlarge street-level windows, which are dungeon-like although higher-floor windows are arched and tall. Larger glass panes are needed especially on the Greenwich Street side.

There’s precedent: Over some preservationists’ howls, the LPC permitted Tishman Speyer to enlarge Rockefeller Center store windows several years ago.

Downtown’s greatest need is for better shopping options, and the Trinity Place conversion will occur as acres of new retail space are coming on line at the World Trade Center one block north.

Neither Fried nor the LPC would comment on any private discussions. But a source said the LPC decided to move ahead with designating 86 Trinity Place “only after a lot of work with the owner.”

A source close to Fried said he wouldn’t ask the LPC for a particular change to the façade until he has a store tenant or several tenants lined up — and thus knew what was needed.

The vote on 86 Trinity Place looms as the LPC is besieged on several fronts.

No fewer than 10 different bills in the City Council would curb or limit the LPC’s authority in various ways, including putting time limits on how long it can consider a property for designation once it’s been “calendared,” and easing restrictions the LPC now puts on materials an owner may use to replace features on properties within a swelling number of designated historic districts.

It isn’t clear when the bills would be voted on, but a source said “many more hearings” would be held first — and several of them were more about “letting off steam.”

Meanwhile, a lobbying and media campaign led by the Real Estate Board of New York — calling itself the Responsible Landmarks Coalition — has targeted what it calls a “broken” landmarks process, which it says affords equal protection to true landmarks and eyesores like gas stations in historic districts.